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Search for Permanent Electric Dipole Moments of Francium Atom

Yasuhiro SAKEMI Research Center for Nuclear Physics (RCNP)

Osaka University

ECR Ion source + Beam line to transport the heavy ions from AVF+

Trap/Cooling Technique↓

Atom EDM search ~ T violation

Time Reversal and EDM

Time Reversal Symmetry ~ Violation ? ~ Test !Dominance of Matter over Antimatter in Universe ?

CPT ~ invariant in quantum field theory : No evidence of violationC: Charge Conjugation ~ violation in weak interaction P: Parity ~ violation in weak interaction T: Time Reversal ~ No evidence of violation

CP: violation was found ~ K0, B decayCPT theorem + CP violation → T violation ?

+-

+-

d

s

T

Electric Dipole Moment

1. Neutron EDM2. Atom EDM

Electron ~ paramagnetic Nucleus (proton) ~ diamagnetic

3. Other particles (ν,μ,τ,Λ0….)

if EDM is observed ~ Beyond the Standard Model

if EDM is measured ~ signal of supersymmetry~ mechanism of SUSY violation

EDM

1.E-38

1.E-35

1.E-32

1.E-29

1.E-26

1.E-23

1.E-20

1.E-17

1.E-14

1.E-11

1.E-08

1945 1955 1965 1975 1985 1995 2005

Year

ED

M(e

cm

) Tl

Supersymmetric: <10-27

Left-right symmetric: 10-26 to 10-28

Higgs models: 3×10-27 to 10-28

Lepton flavor-changing:10-26 to 10-29

Standard model: < 10-38

Best current limit EDM : |de|<1.5×10-27 e・cm from E.D.Commins et al (California), Tl

A challenge is set !

EDM and MSSM

2

sin~

MµθElectron EDM in MSSM → limit to CP-violating phase in MSSM

eL eRγ~

e~

EDM Measurement and Sensitivity

E E

EdhEdBhEdBh

⋅=∆⇒

⋅−⋅=

⋅+⋅=

↑↓

↑↑

42222

νµνµν

Electric dipole moment : d

TNEKehd

⋅⋅⋅⋅⋅=

τδ 111

2Sensitivity :

K: Enhancement factor ~ Atom EDM enhancement E : Electric Field ~ Strong, 100 kV/cm N : Number of Particles ~ Many particles !τ: Coherence Time (Stored time) ~ Long ! (relaxation…) T : Lifetime of Experimentalist ~ Long !

23~ αZd

d

e

atom

∑

∑∑∑

∑

⋅−+

∇⋅+

∇⋅=

−=

≠

iiiie

kjjk

iii

e

iii

e

iiiie

Ed

BedH

ed

EdH

σβ

σσ

σβ

)1(

21,,

'

0

Enhancement factor

0

200

400

600

800

1000

1200

1400

0 20 40 60 80 100

K

Char

ge :

Z

Enhancement factor simple

RbXe Cs

Tl

Fr

Enha

ncem

ent f

acto

r

Charge :Z

Enhancement effects for Atomic EDM

Heaviest Alkali Atom : Francium 210Fr ~ K=1150

1939 found Atomic number 87 Average atomic weight 215 Ionization Potential 4.08 eVRadioactive lifetime of Fr210 =3.2 minNo stable isotopes ~ longest lifetime 223Fr: 22min.

Relativistic effect

Unique points of experiment

1. Heaviest Alkali Atom : Francium EDM enhancement factor :K=1150 ~ Maximum Produced by fusion reaction with high intensity ECR ion source + AVF cyclotronReaction 18/16O + 197Au → 207-211Fr + Xn

2. Extremely cold atom : Bose-Einstein Condensation (BEC) production techniqueCoherence time : τ ~ Long Atoms localized ~ 10 μm order → Applied electric field : E ~ constant High vacuum → High electric field : E ~ possible Ultra cold → small effect of kinematical magnetic field : v×E

3. Rapid cooling ~ Radioactive atom with finite life time ( ~ minutes)Chip trap = Magnetic trap + Evaporation cooling : N,T ~ large

Present status

Micro-Trap

MOT

Atomic beamMOTMOT/PenningMOTTrap

171Yb (p) KyotoXe (p)T.I.T.

TISOLTRIUMFBest limit 205Tl (e)California / LBL

No plan…207-211FrRCNP

First beam Ra (p)TRIuPKVIAtomic structure210FrSUNY

Goal Status Elements ProjectInstitute

Dy,Sm,BaFr

Yb

205TlRa

129Xe 3P2

Others199HgRn129Xe 1S0Nucleus OthersFe3+CsRbElectron

Elements EDM

Experimental Overview

Au targetY neutralizer

Ion transport lenses

18O beam from AVF cyclotron

Cell

Trapped Francium

Chip for Magnetic Trap

Laser Beam

Fr+ ion

Francium production

Fusion Reaction : 18/16O + 197Au → 207-211Fr + Xn

Francium desorbs from the target surface as atoms/ions according to

−

=+

kTEE

nn IPWFexp

21

0

18O beam from AVF

Au target Y targetFr+ ion

Fr atom

To Trap/Cooling

Fr/sec

0

50000

100000

150000

18O Beam Energy (MeV)70 80 90 100 110 120

Francium intensities @ 0.1 uA

210/211Fr

208/209Fr

Target : Gold (Au) ~ EWF(5.1eV)>EIP(4.1eV) → Fr+ ionTarget : Yttrium (Y) ~ EWF(3.1eV)<EIP(4.1eV) → Fr atom

Path to extremely Cold AtomReaction product mud be slowed and cooled from MeV to nano-eV

Magneto-Optical Trap (MOT)

Francium production : 18O + 197Au = 210Fr + 5n

Magnetic Trap and Evaporation Cooling < uK

Bose-Einstein Condensation (BEC)

100 MeV Primary Beam (18O) from AVF cyclotron

Transport Francium

Stop in neutralizer

Vapor in Gas Cell

Laser Trap < nK

Radioactive Atom Finite life time

Fast Trapping/Cooling

MeV

keV

eV

meV

μeV

neV

Microchip Trap

Magnetic trap Realization on Chip Trap for BEC at MPQ

)()( rBurV m ⋅=

r Rapid coolingCompact/easy constructionAtom control ~ magnetic conveyor belt

Microchip Trap

2002Summer

MPQ

Developed at Max-Planck-Institute for Quantum Optics (MPQ) , Prof.Reichel Group

Cooled Atom Collection Sequence

SC-ECR ion source : 18O 1 uA ~100 MeV

1×106 Fr/s production

MOT : 6×106 atoms 6 sec. ~ accumulation

Transfer : MOT to Magnetic Trap

2 sec. ~ accomplished Magnetic Trap : evaporation cooling : 6000 atoms

Measurement Optical Trap : Francium (BEC) : 6000 atoms

EDM measurement with Ultra Cold Francium ~ 10 sec. cycle

EDM measurement

2810~1112

−

⋅⋅⋅⋅⋅=

TNEKehd

τδ

Enhancement factor : K=1150 for Fr E~100kV/cm Coherence time : τ~ 1 sN~6000 atoms @ 1 uA 18O beam

Measurement time : T ~ 60 days needed

If we have 10 days beam time / year → 6years If we have 10 μA ……

Collection efficiency : trapping/cooling technique ECR ion source ~ High intensity Radiation protectionLow cost ~ AVF cyclotron only , RING cyclotron NOT used..Not so much effect to beam time ~ no effect to main physics program at RCNP (high resolution, spin-isospin, cluster…)

Required machine specification

? Fr transport BLS exp. Room? Exist 東 or 西実験室Experimental room

Collaboration 外部資金（2004以降）Rapid cooling Micro Trap

2004in progress Transport to 東・西Beam Line 2004SC ECR 18-24 GHz16/18O : 1~10 μAHeavy Ion Source

Comments Plan Required Spec. Equipments

Physics Experimental feasibility ~ Trap/Cooling technique P-PAC, LOIBudget

Time line ~ other institute (SUNY ..) … ~ within 2 or 3 years

Possibility at RCNP

Beam Line

東実験室

西実験室 リング本体室

中性子実験室New Beam Line1. Nuclear physics ~ heavy ion :

Nuclear magnetic moment 不安定核原子のレーザー核分光Polarized 6Li ion beam Material physics High resolution physics

2. Beam Diagnosis for High Resolution beam3. Basic Physics : Permanent EDM search4. Application

Function : Beam transport ~ achromatic mode (東、西、中性子)Beam diagnosis ~ dispersive mode

Summary

1. Search for permanent EDM of Francium atom Time reversal violation : Test

2. Experimental technique : ECR ion source + AVF direct beam line → Francium atom production New technique : Trap/Cooling ~ collaboration ..

3. Physics with accurate measurement using Trapped/Cooled Atom